summaryrefslogtreecommitdiff
path: root/sql/sql_udf.cc
blob: 74d2f6bc252dad92ef87770c9507c1801fe6b133 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
/* Copyright (c) 2000, 2012, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

/* This implements 'user defined functions' */

/*
   Known bugs:
  
   Memory for functions is never freed!
   Shared libraries are not closed before mysqld exits;
     - This is because we can't be sure if some threads are using
       a function.
  
   The bugs only affect applications that create and free a lot of
   dynamic functions, so this shouldn't be a real problem.
*/

#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation				// gcc: Class implementation
#endif

#include <my_global.h>
#include "sql_priv.h"
#include "unireg.h"
#include "sql_base.h"                           // close_mysql_tables
#include "sql_parse.h"                        // check_identifier_name
#include "sql_table.h"                        // write_bin_log
#include "records.h"          // init_read_record, end_read_record
#include <my_pthread.h>
#include "lock.h"                               // MYSQL_LOCK_IGNORE_TIMEOUT

#ifdef HAVE_DLOPEN
extern "C"
{
#include <stdarg.h>
#include <hash.h>
}

static bool initialized = 0;
static MEM_ROOT mem;
static HASH udf_hash;
static mysql_rwlock_t THR_LOCK_udf;


static udf_func *add_udf(LEX_STRING *name, Item_result ret,
                         char *dl, Item_udftype typ);
static void del_udf(udf_func *udf);
static void *find_udf_dl(const char *dl);

static char *init_syms(udf_func *tmp, char *nm)
{
  char *end;

  if (!((tmp->func= (Udf_func_any) dlsym(tmp->dlhandle, tmp->name.str))))
    return tmp->name.str;

  end=strmov(nm,tmp->name.str);

  if (tmp->type == UDFTYPE_AGGREGATE)
  {
    (void)strmov(end, "_clear");
    if (!((tmp->func_clear= (Udf_func_clear) dlsym(tmp->dlhandle, nm))))
      return nm;
    (void)strmov(end, "_add");
    if (!((tmp->func_add= (Udf_func_add) dlsym(tmp->dlhandle, nm))))
      return nm;
  }

  (void) strmov(end,"_deinit");
  tmp->func_deinit= (Udf_func_deinit) dlsym(tmp->dlhandle, nm);

  (void) strmov(end,"_init");
  tmp->func_init= (Udf_func_init) dlsym(tmp->dlhandle, nm);

  /*
    to prefent loading "udf" from, e.g. libc.so
    let's ensure that at least one auxiliary symbol is defined
  */
  if (!tmp->func_init && !tmp->func_deinit && tmp->type != UDFTYPE_AGGREGATE)
  {
    if (!opt_allow_suspicious_udfs)
      return nm;
    if (current_thd->variables.log_warnings)
      sql_print_warning(ER(ER_CANT_FIND_DL_ENTRY), nm);
  }
  return 0;
}


extern "C" uchar* get_hash_key(const uchar *buff, size_t *length,
			      my_bool not_used __attribute__((unused)))
{
  udf_func *udf=(udf_func*) buff;
  *length=(uint) udf->name.length;
  return (uchar*) udf->name.str;
}

#ifdef HAVE_PSI_INTERFACE
static PSI_rwlock_key key_rwlock_THR_LOCK_udf;

static PSI_rwlock_info all_udf_rwlocks[]=
{
  { &key_rwlock_THR_LOCK_udf, "THR_LOCK_udf", PSI_FLAG_GLOBAL}
};

static void init_udf_psi_keys(void)
{
  const char* category= "sql";
  int count;

  if (PSI_server == NULL)
    return;

  count= array_elements(all_udf_rwlocks);
  PSI_server->register_rwlock(category, all_udf_rwlocks, count);
}
#endif

/*
  Read all predeclared functions from mysql.func and accept all that
  can be used.
*/

void udf_init()
{
  udf_func *tmp;
  TABLE_LIST tables;
  READ_RECORD read_record_info;
  TABLE *table;
  int error;
  DBUG_ENTER("ufd_init");
  char db[]= "mysql"; /* A subject to casednstr, can't be constant */

  if (initialized || opt_noacl)
    DBUG_VOID_RETURN;

#ifdef HAVE_PSI_INTERFACE
  init_udf_psi_keys();
#endif

  mysql_rwlock_init(key_rwlock_THR_LOCK_udf, &THR_LOCK_udf);

  init_sql_alloc(&mem, UDF_ALLOC_BLOCK_SIZE, 0, MYF(0));
  THD *new_thd = new THD;
  if (!new_thd ||
      my_hash_init(&udf_hash,system_charset_info,32,0,0,get_hash_key, NULL, 0))
  {
    sql_print_error("Can't allocate memory for udf structures");
    my_hash_free(&udf_hash);
    free_root(&mem,MYF(0));
    delete new_thd;
    DBUG_VOID_RETURN;
  }
  initialized = 1;
  new_thd->thread_stack= (char*) &new_thd;
  new_thd->store_globals();
  new_thd->set_db(db, sizeof(db)-1);

  tables.init_one_table(db, sizeof(db)-1, "func", 4, "func", TL_READ);

  if (open_and_lock_tables(new_thd, &tables, FALSE, MYSQL_LOCK_IGNORE_TIMEOUT))
  {
    DBUG_PRINT("error",("Can't open udf table"));
    sql_print_error("Can't open the mysql.func table. Please "
                    "run mysql_upgrade to create it.");
    goto end;
  }

  table= tables.table;
  if (init_read_record(&read_record_info, new_thd, table, NULL,1,0,FALSE))
  {
    sql_print_error("Could not initialize init_read_record; udf's not "
                    "loaded");
    goto end;
  }

  table->use_all_columns();
  while (!(error= read_record_info.read_record(&read_record_info)))
  {
    DBUG_PRINT("info",("init udf record"));
    LEX_STRING name;
    name.str=get_field(&mem, table->field[0]);
    name.length = (uint) strlen(name.str);
    char *dl_name= get_field(&mem, table->field[2]);
    bool new_dl=0;
    Item_udftype udftype=UDFTYPE_FUNCTION;
    if (table->s->fields >= 4)			// New func table
      udftype=(Item_udftype) table->field[3]->val_int();

    /*
      Ensure that the .dll doesn't have a path
      This is done to ensure that only approved dll from the system
      directories are used (to make this even remotely secure).

      On windows we must check both FN_LIBCHAR and '/'.
    */
    if (check_valid_path(dl_name, strlen(dl_name)) ||
        check_string_char_length(&name, "", NAME_CHAR_LEN,
                                 system_charset_info, 1))
    {
      sql_print_error("Invalid row in mysql.func table for function '%.64s'",
                      name.str);
      continue;
    }

    if (!(tmp= add_udf(&name,(Item_result) table->field[1]->val_int(),
                       dl_name, udftype)))
    {
      sql_print_error("Can't alloc memory for udf function: '%.64s'", name.str);
      continue;
    }

    void *dl = find_udf_dl(tmp->dl);
    if (dl == NULL)
    {
      char dlpath[FN_REFLEN];
      strxnmov(dlpath, sizeof(dlpath) - 1, opt_plugin_dir, "/", tmp->dl,
               NullS);
      (void) unpack_filename(dlpath, dlpath);
      if (!(dl= dlopen(dlpath, RTLD_NOW)))
      {
	/* Print warning to log */
        sql_print_error(ER(ER_CANT_OPEN_LIBRARY), tmp->dl, errno, dlerror());
	/* Keep the udf in the hash so that we can remove it later */
	continue;
      }
      new_dl=1;
    }
    tmp->dlhandle = dl;
    {
      char buf[SAFE_NAME_LEN+16], *missing;
      if ((missing= init_syms(tmp, buf)))
      {
        sql_print_error(ER(ER_CANT_FIND_DL_ENTRY), missing);
        del_udf(tmp);
        if (new_dl)
          dlclose(dl);
      }
    }
  }
  if (error > 0)
    sql_print_error("Got unknown error: %d", my_errno);
  end_read_record(&read_record_info);
  table->m_needs_reopen= TRUE;                  // Force close to free memory

end:
  close_mysql_tables(new_thd);
  delete new_thd;
  DBUG_VOID_RETURN;
}


void udf_free()
{
  /* close all shared libraries */
  DBUG_ENTER("udf_free");
  if (opt_noacl)
    DBUG_VOID_RETURN;
  for (uint idx=0 ; idx < udf_hash.records ; idx++)
  {
    udf_func *udf=(udf_func*) my_hash_element(&udf_hash,idx);
    if (udf->dlhandle)				// Not closed before
    {
      /* Mark all versions using the same handler as closed */
      for (uint j=idx+1 ;  j < udf_hash.records ; j++)
      {
	udf_func *tmp=(udf_func*) my_hash_element(&udf_hash,j);
	if (udf->dlhandle == tmp->dlhandle)
	  tmp->dlhandle=0;			// Already closed
      }
      dlclose(udf->dlhandle);
    }
  }
  my_hash_free(&udf_hash);
  free_root(&mem,MYF(0));
  if (initialized)
  {
    initialized= 0;
    mysql_rwlock_destroy(&THR_LOCK_udf);
  }
  DBUG_VOID_RETURN;
}


static void del_udf(udf_func *udf)
{
  DBUG_ENTER("del_udf");
  if (!--udf->usage_count)
  {
    my_hash_delete(&udf_hash,(uchar*) udf);
    using_udf_functions=udf_hash.records != 0;
  }
  else
  {
    /*
      The functions is in use ; Rename the functions instead of removing it.
      The functions will be automaticly removed when the least threads
      doesn't use it anymore
    */
    char *name= udf->name.str;
    uint name_length=udf->name.length;
    udf->name.str=(char*) "*";
    udf->name.length=1;
    my_hash_update(&udf_hash,(uchar*) udf,(uchar*) name,name_length);
  }
  DBUG_VOID_RETURN;
}


void free_udf(udf_func *udf)
{
  DBUG_ENTER("free_udf");
  
  if (!initialized)
    DBUG_VOID_RETURN;

  mysql_rwlock_wrlock(&THR_LOCK_udf);
  if (!--udf->usage_count)
  {
    /*
      We come here when someone has deleted the udf function
      while another thread still was using the udf
    */
    my_hash_delete(&udf_hash,(uchar*) udf);
    using_udf_functions=udf_hash.records != 0;
    if (!find_udf_dl(udf->dl))
      dlclose(udf->dlhandle);
  }
  mysql_rwlock_unlock(&THR_LOCK_udf);
  DBUG_VOID_RETURN;
}


/* This is only called if using_udf_functions != 0 */

udf_func *find_udf(const char *name,uint length,bool mark_used)
{
  udf_func *udf=0;
  DBUG_ENTER("find_udf");

  if (!initialized)
    DBUG_RETURN(NULL);

  DEBUG_SYNC(current_thd, "find_udf_before_lock");
  /* TODO: This should be changed to reader locks someday! */
  if (mark_used)
    mysql_rwlock_wrlock(&THR_LOCK_udf);  /* Called during fix_fields */
  else
    mysql_rwlock_rdlock(&THR_LOCK_udf);  /* Called during parsing */

  if ((udf=(udf_func*) my_hash_search(&udf_hash,(uchar*) name,
                                      length ? length : (uint) strlen(name))))
  {
    if (!udf->dlhandle)
      udf=0;					// Could not be opened
    else if (mark_used)
      udf->usage_count++;
  }
  mysql_rwlock_unlock(&THR_LOCK_udf);
  DBUG_RETURN(udf);
}


static void *find_udf_dl(const char *dl)
{
  DBUG_ENTER("find_udf_dl");

  /*
    Because only the function name is hashed, we have to search trough
    all rows to find the dl.
  */
  for (uint idx=0 ; idx < udf_hash.records ; idx++)
  {
    udf_func *udf=(udf_func*) my_hash_element(&udf_hash,idx);
    if (!strcmp(dl, udf->dl) && udf->dlhandle != NULL)
      DBUG_RETURN(udf->dlhandle);
  }
  DBUG_RETURN(0);
}


/* Assume that name && dl is already allocated */

static udf_func *add_udf(LEX_STRING *name, Item_result ret, char *dl,
			 Item_udftype type)
{
  if (!name || !dl || !(uint) type || (uint) type > (uint) UDFTYPE_AGGREGATE)
    return 0;
  udf_func *tmp= (udf_func*) alloc_root(&mem, sizeof(udf_func));
  if (!tmp)
    return 0;
  bzero((char*) tmp,sizeof(*tmp));
  tmp->name = *name; //dup !!
  tmp->dl = dl;
  tmp->returns = ret;
  tmp->type = type;
  tmp->usage_count=1;
  if (my_hash_insert(&udf_hash,(uchar*)  tmp))
    return 0;
  using_udf_functions=1;
  return tmp;
}


/**
  Create a user defined function. 

  @note Like implementations of other DDL/DML in MySQL, this function
  relies on the caller to close the thread tables. This is done in the
  end of dispatch_command().
*/

int mysql_create_function(THD *thd,udf_func *udf)
{
  int error;
  void *dl=0;
  bool new_dl=0;
  TABLE *table;
  TABLE_LIST tables;
  udf_func *u_d;
  DBUG_ENTER("mysql_create_function");

  if (!initialized)
  {
    if (opt_noacl)
      my_error(ER_CANT_INITIALIZE_UDF, MYF(0),
               udf->name.str,
               "UDFs are unavailable with the --skip-grant-tables option");
    else
      my_message(ER_OUT_OF_RESOURCES, ER(ER_OUT_OF_RESOURCES), MYF(0));
    DBUG_RETURN(1);
  }

  /*
    Ensure that the .dll doesn't have a path
    This is done to ensure that only approved dll from the system
    directories are used (to make this even remotely secure).
  */
  if (check_valid_path(udf->dl, strlen(udf->dl)))
  {
    my_message(ER_UDF_NO_PATHS, ER(ER_UDF_NO_PATHS), MYF(0));
    DBUG_RETURN(1);
  }
  if (check_string_char_length(&udf->name, "", NAME_CHAR_LEN,
                               system_charset_info, 1))
  {
    my_error(ER_TOO_LONG_IDENT, MYF(0), udf->name.str);
    DBUG_RETURN(1);
  }

  tables.init_one_table(STRING_WITH_LEN("mysql"), STRING_WITH_LEN("func"),
                        "func", TL_WRITE);
  table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);

  mysql_rwlock_wrlock(&THR_LOCK_udf);
  DEBUG_SYNC(current_thd, "mysql_create_function_after_lock");
  if ((my_hash_search(&udf_hash,(uchar*) udf->name.str, udf->name.length)))
  {
    my_error(ER_UDF_EXISTS, MYF(0), udf->name.str);
    goto err;
  }
  if (!(dl = find_udf_dl(udf->dl)))
  {
    char dlpath[FN_REFLEN];
    strxnmov(dlpath, sizeof(dlpath) - 1, opt_plugin_dir, "/", udf->dl, NullS);
    (void) unpack_filename(dlpath, dlpath);

    if (!(dl = dlopen(dlpath, RTLD_NOW)))
    {
      DBUG_PRINT("error",("dlopen of %s failed, error: %d (%s)",
                          udf->dl, errno, dlerror()));
      my_error(ER_CANT_OPEN_LIBRARY, MYF(0),
               udf->dl, errno, dlerror());
      goto err;
    }
    new_dl=1;
  }
  udf->dlhandle=dl;
  {
    char buf[SAFE_NAME_LEN+16], *missing;
    if ((missing= init_syms(udf, buf)))
    {
      my_error(ER_CANT_FIND_DL_ENTRY, MYF(0), missing);
      goto err;
    }
  }
  udf->name.str=strdup_root(&mem,udf->name.str);
  udf->dl=strdup_root(&mem,udf->dl);
  if (!(u_d=add_udf(&udf->name,udf->returns,udf->dl,udf->type)))
    goto err;
  u_d->dlhandle = dl;
  u_d->func=udf->func;
  u_d->func_init=udf->func_init;
  u_d->func_deinit=udf->func_deinit;
  u_d->func_clear=udf->func_clear;
  u_d->func_add=udf->func_add;

  /* create entry in mysql.func table */

  /* Allow creation of functions even if we can't open func table */
  if (!table)
    goto err;
  table->use_all_columns();
  restore_record(table, s->default_values);	// Default values for fields
  table->field[0]->store(u_d->name.str, u_d->name.length, system_charset_info);
  table->field[1]->store((longlong) u_d->returns, TRUE);
  table->field[2]->store(u_d->dl,(uint) strlen(u_d->dl), system_charset_info);
  if (table->s->fields >= 4)			// If not old func format
    table->field[3]->store((longlong) u_d->type, TRUE);
  error = table->file->ha_write_row(table->record[0]);

  if (error)
  {
    my_error(ER_ERROR_ON_WRITE, MYF(0), "mysql.func", error);
    del_udf(u_d);
    goto err;
  }
  mysql_rwlock_unlock(&THR_LOCK_udf);

  /* Binlog the create function. */
  if (write_bin_log(thd, TRUE, thd->query(), thd->query_length()))
    DBUG_RETURN(1);

  DBUG_RETURN(0);

 err:
  if (new_dl)
    dlclose(dl);
  mysql_rwlock_unlock(&THR_LOCK_udf);
  DBUG_RETURN(1);
}


int mysql_drop_function(THD *thd,const LEX_STRING *udf_name)
{
  TABLE *table;
  TABLE_LIST tables;
  udf_func *udf;
  char *exact_name_str;
  uint exact_name_len;
  DBUG_ENTER("mysql_drop_function");

  if (!initialized)
  {
    if (opt_noacl)
      my_error(ER_FUNCTION_NOT_DEFINED, MYF(0), udf_name->str);
    else
      my_message(ER_OUT_OF_RESOURCES, ER(ER_OUT_OF_RESOURCES), MYF(0));
    DBUG_RETURN(1);
  }

  tables.init_one_table(STRING_WITH_LEN("mysql"), STRING_WITH_LEN("func"),
                        "func", TL_WRITE);
  table= open_ltable(thd, &tables, TL_WRITE, MYSQL_LOCK_IGNORE_TIMEOUT);

  mysql_rwlock_wrlock(&THR_LOCK_udf);
  DEBUG_SYNC(current_thd, "mysql_drop_function_after_lock");
  if (!(udf=(udf_func*) my_hash_search(&udf_hash,(uchar*) udf_name->str,
                                       (uint) udf_name->length)))
  {
    my_error(ER_FUNCTION_NOT_DEFINED, MYF(0), udf_name->str);
    goto err;
  }
  exact_name_str= udf->name.str;
  exact_name_len= udf->name.length;
  del_udf(udf);
  /*
    Close the handle if this was function that was found during boot or
    CREATE FUNCTION and it's not in use by any other udf function
  */
  if (udf->dlhandle && !find_udf_dl(udf->dl))
    dlclose(udf->dlhandle);

  if (!table)
    goto err;
  table->use_all_columns();
  table->field[0]->store(exact_name_str, exact_name_len, &my_charset_bin);
  if (!table->file->ha_index_read_idx_map(table->record[0], 0,
                                          (uchar*) table->field[0]->ptr,
                                          HA_WHOLE_KEY,
                                          HA_READ_KEY_EXACT))
  {
    int error;
    if ((error = table->file->ha_delete_row(table->record[0])))
      table->file->print_error(error, MYF(0));
  }
  mysql_rwlock_unlock(&THR_LOCK_udf);

  /*
    Binlog the drop function. Keep the table open and locked
    while binlogging, to avoid binlog inconsistency.
  */
  if (write_bin_log(thd, TRUE, thd->query(), thd->query_length()))
    DBUG_RETURN(1);

  DBUG_RETURN(0);

err:
  mysql_rwlock_unlock(&THR_LOCK_udf);
  DBUG_RETURN(1);
}

#endif /* HAVE_DLOPEN */